New Triple X carb install, now backfires

[ChopperJeff]

Finally got the new Triple X 'E' carb installed. It replaced my stock Super 'E', and I removed the restrictor plates (actually bored them out to maintain the spacer funcationality of the thing).

Now the bike backfires like crazy, especially when throttle is applied. I adjusted the idle fuel/mixture screw according to the instructions. Even at idle though it backfire a little bit, but it's not too bad.

Is this just an indicator that my jetting is now WAY off, or is there something else I should be looking at?

Thanks!

 

[Redflames02]

Most often an air/fuel mix problem. Backfiring through the carb indicates that your carb is running lean. Starving for gas. Try to readjust carb again. If that don't help rejet the carb. It just a matter of getting the air/fuel mixture right.

 

[Raywood]

Finally got the new Triple X 'E' carb installed. It replaced my stock Super 'E', and I removed the restrictor plates (actually bored them out to maintain the spacer funcationality of the thing).

Now the bike backfires like crazy, especially when throttle is applied. I adjusted the idle fuel/mixture screw according to the instructions. Even at idle though it backfire a little bit, but it's not too bad.

Is this just an indicator that my jetting is now WAY off, or is there something else I should be looking at?

Thanks!

Jeff, are the jets the same?
You're carb is now slightly larger so will allow more air through. This will require a slightly larger jet to richen it back up.
Were you careful replacing the intake seals? I use Vaseline to ensure they slide on properly without kinking. I would ensure you don't have an intake leak.
Did you also replace the aircleaner? If so then "more air" so need to richen it up some more.
Again, what jets were in it and what did Bob send in your new one?

Oh, turn off the accelerator pump while adjusting then when done back it out 1 1/2 to 2 turns.

 

[lee]

I agree with Ray - could be an intake leak seeing as you bored out the restrictor plates. With the engine running spray some brake cleaner on there and listen for a change in rpm's. If there is a change you got a leak.

 

[ChopperJeff]

Thanks guys for the input!

I also sent an email to Triple X last night, and this morning (Sunday), I got an email from Bob detailing all the things to check. Needless to say I was VERY impressed! He also said to call him if I have any further issues.

Here's what I ended up doing and emailed Bob back with:

One thing I noticed when looking at the pictures I took of my old carb before removing it is that there was an inlet capped with a rubber stopper. I then realized that when I installed the new carb, this “cap” was missing. I went ahead and put this “cap” on, then proceeded to adjust the idle fuel/air mixture screw with the accelerator pump turned off by tightening its screw all the way. After tweaking things a bit, the bike seemed to be running OK, but it seemed like there was a lot of heat. I looked down and saw that the exhaust pipe going to the front cylinder was literally glowing red hot! After shutting the bike down and letting it cool, I started it back up and adjusted the accelerator pump screw by letting it out a bit. The pipe never glowed again, so I went for a ride. It seemed to ride OK with just a little popping from the exhaust on decal, but this seemed normal.

The only thing I noticed was that at a constant speed of around 30 mph it seemed to “stumble” a bit, but that sensation was pretty subtle.

Next will be the installation of the Bassani Pro-street pipes followed by another dyno run to get everything set correctly.

Thank again guys for your input!

Ride safe.

 

[Gas Man]

What are the jet sizes?

That must be checked!

 

[ChopperJeff]

Bob was not at the shop when he emailed me, but believes they installed a .076 main, a .031 intermediate jet and a .050 air bleed.

 

[Staffy]

All signs of running lean...at 30 mph - what's your RPM at that time? Around 2500? Only thing that get me is the red hot pipe - this is usually and typically is the case with the rear cylinder, either way it points to running lean (or an intake leak - any chance this could be the case, specially when removing/installing the carb? Do the spray gig and check:lol: :lol: ) After some riding, check your plugs as well. Good luck. Finally which air filter do you have?

 

[lee]

Jeff - it worries me how you say you tightened the acc pump screw all the way in - you only need to turn it in until you first feel resistance

 

[ChopperJeff]

When I stated that I tightened the acc pump screw all the way, I really meant that I turned it clockwise until I felt resistance, then I stopped.

And yes, at 30 MPH I'd say I was at about 2500 RPM.

I guess the next logical step is to get a hold of some spray brake cleaner and check for an intake leak, especially for the front cyclinder.

 

[rhinoevans]

BOB did my carb a few months back. Was having HP problems, which turned out to be a very restrictive exhaust. Anyway, BOB tuned my card for his test motor, and my motor was way different. I always just drop $120 at the local dyno to get it right. I tried for days to get it tuned my self, followed all the directions and was unsuccessful. Turns out my inter jet need increased. It was a 295. I put in a 31 and the dyno called for a 33. Also had problems on the accelerator pump adjustment. The 2-2 1/2 turns did not work for me. I had Bob change out all the adjustment screws and for some reason the new accelerator pump screw was more sensitive. Required more turns to get it right, and remove the stumble I had when twisting the throttle. Just a thought.

 

[ChopperJeff]

I figure I'm not going to get it perfect, but want to get it dialed in well enough to ride the 80 miles to the place I get it dyno'd at. Also, if I have an intake leak, I'd just assume find that and fix it myself instead of paying the mechanics $80/hour.

By the way... has anybody has any luck with coating the inside of the pipes with something to help prevent discoloration? I've seen that some people get it ceramic coated, but I don't think I can afford that. I'm already stretching it to just get the carb and the new Bassani pipes, plus dynoing.

Thanks everyone for you input!

 

[Cutter]

I was told:
Ceramic Coating will SLOW the Blueing Processs and keep it closer to the heads...
and possibly keep the gases hotter for better flow? -maybe add a couple hp or not?

 

[lee]

Jeff what intake do you have on there? have you tried removing the bowl vent screw?

 

[ChopperJeff]

Lee - I just have the stock intake. And no, I have not tried removing the bowl vent screw.

 

[ChopperJeff]

OK, my new pipes are to be here Thursday and I'm scheduled for a dyno on Saturday!

Rather strange though that when I told the guy that will be doing the dyno that I got a new and improved carb installed with the restrictor plates removed, he said that with the same intake manifold that it won't make any difference. That really confuses me as how the heck can opening up an intake hole from about 1.25" to about 1.75" not help? Maybe he's thinking that the opening to the carb needs to be bigger to really get an improvement?

As a refresher course here, I went with the Triple X carb and Bassani Pro-Street pipes, and keeping the stock intake with the K&N air filter.

 

[woodbutcher]

may have to look into the 3" k&n filter and the louver/screen front cover on the intake. never ending. good luck.

 

[TAZMAN]

Hello from TRIPLE x CARBS

Here's some responses I made with Jeff lately and hope all is ironed ouit by now. If anyone has a problem with the S&S carb I'll be glad to help out anytime. Remember, all individual BDOF members now are eligible for a 10% discount on all our carbs.

-----Original Message-----
From: Bob Maltz [mailto:xxxcarburetors@yahoo.com]
Sent: Sunday, November 16, 2008 8:20 AM
To: Jeff Szlauko
Subject: Re: HELP! New Carb is causing backfires



Hi Jeff,

First explain what you mean by backfires? Does the engine pop thru the exhaust or is it sneezing thru the carb? The word backfire can describe a lot of things but may not zero in on the real problem.

We jet our carbs according to engine size and from customer feedback to get the best possible starting point. Every bike is a little different and may need a little tweaking but the jets will be pretty close regardless. I believe we installed a .076 main, a .031 intermediate jet and a .050 air bleed for you size engine. I'm not at the shop at the moment but those would be the sizes I would use. Also we test all carbs going out on a V-Twin test motor to make sure it operates properly before it leaves here.

If your engine is sneezing (backfires) from the carb when you give it the throttle then it could be caused by a couple of things. Most common is an intake leak that is leaning out the mixture causing the flame to travel from the cylinder back out the carb. A missing or damaged 'O' ring on the carb flange or a leaking intake pipe seal at the head can do this. Another possibility is the accelerator pump may need to be adjusted out a little more. Back out the screw on the right side as you face the carb, out gives the carb more fuel and in gives it less when opening the throttle.

Another thing that may be sensitive is the idle mixture setting. With engine shut off screw the idle mix screw in until it gently stops, be careful not to over tighten this screw or you will damage carb. Then back out the idle mix screw 2 full turns and stop, this should be a good starting point. Start and warm up engine and then turn in the idle mix screw slowly until engine begins to speed up and smooth out slightly. If the engine does this then back out the screw about 1/4 turn or when engine begins to slow down and stop. Idle mix is now correct. If the engine started to slow down right away as you moved the idle mix screw in from the 2 turn out position then the back out the screw until the engine runs smoothly and stop. This may indicate that the intermediate jet is too small (more than 2 turns out and assuming there is no intake leaks) and you may have to go up a size or two. If you have to change the int. jet then you will need to readjust the idle mix again as above. I usually set the idle mix slightly on the rich side (about a 1/4 turn out) for best acceleration.

If engine is popping out the exhaust when backing off on the throttle then the accelerator pump adjustment may be set out too far. Screw in the far right adjustment screw about a 1/4 turn at a time until engine hesitates when opening the throttle then back out screw 1/4 turn and engine accelerates smoothly. Check idle mix adjustment too. Most engines don't backfire or pop out the exhaust when opening the throttle and this may not be the case for your engine.

When you installed the TRIPLE X CARB did you install a different air cleaner assembly? Either way did you make sure the carbs bowl breather hole (the hole located at the far left center of carb face as you look at the front of carb) is not covered up and is open to the air cleaner. If this breather hole is covered up with a new gasket and/or air cleaner assembly it will let engine run and idle but it will run terrible above the idle speed. If this is happening and you can't uncover this hole because of air cleaner design then you will need to remove an alternate bowl breather hole plug located just below the original hole. This plug is a hex style plug and an allen wrench will remove it. Remove this plug and see if the problem goes away. If it does then vent was the problem.

Let me know what you found out or call, 936-788-3245.

Bob
TRIPLE X CARBURETORS

 

[chaingunner]

:2thumbs:

That is awesome your on here now Bob. Great post!

 

[ChopperJeff]

Yes, I've been VERY impressed with the input from Bob (IE: TAZMAN) since installing the carb. I hope people that read my posts about the carb and the backfiring are not turned away from dealing with Triple X! It's easy for a company to do well when all is going as expected, but it's a true test when the company has to step up to the plate and deal with a customers questions and concerns.

My first email to Bob at Triple X went out on a Saturday night, and Sunday morning there was his reply, along with his phone number in case I needed to speak with him!

Since getting his input I've gotten the bike riding pretty well, and once the new pipes are installed and the bike's dyno'd, I'm sure it will run GREAT!

I'm very impressed with the new carb as far as workmanship and appearance, and have little doubt it will perform as well as it looks once it's professionally dialed in.

I for one welcome Bob and Triple X to this forum, and am a VERY satisfied customer!